The past, in effect, is a tautology; it is true by virtue of its logical form alone.

It doesn't affect the validity of the statement, so you can include it without destroying your tautology.

Some authors treated the quantity theory as a matter of causal relation and explanation, often differing as to the content and direction of explanation, whereas others saw it as a truism, identity or tautology.

Derivatives

tautological

The camp provided the Germans tautological proof of the necessity of imprisoning Untermenschen: the disgusting state of the Haftlinge of Auschwitz demonstrated their inferiority and justified their murder.

What may seem tautological - happiness being happiness - epitomizes Traheme's use of perspectival language: to attempt to move from the subjective and to the objective.

Those who view the question as ultimately tautological, and therefore futile, have a strong case to make; but that is not the same thing as saying the question is without use.